binutils-gdb/gdb/testsuite/gdb.threads/thread-execl.exp
Pedro Alves 95e50b2723 follow-exec: delete all non-execing threads
This fixes invalid reads Valgrind first caught when debugging against
a GDBserver patched with a series that adds exec events to the remote
protocol.  Like these, using the gdb.threads/thread-execl.exp test:

$ valgrind ./gdb -data-directory=data-directory ./testsuite/gdb.threads/thread-execl  -ex "tar extended-remote :9999" -ex "b thread_execler" -ex "c" -ex "set scheduler-locking on"
...
Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29
29        if (execl (image, image, NULL) == -1)
(gdb) n
Thread 32509.32509 is executing new program: build/gdb/testsuite/gdb.threads/thread-execl
[New Thread 32509.32532]
==32510== Invalid read of size 4
==32510==    at 0x5AA7D8: delete_breakpoint (breakpoint.c:13989)
==32510==    by 0x6285D3: delete_thread_breakpoint (thread.c:100)
==32510==    by 0x628603: delete_step_resume_breakpoint (thread.c:109)
==32510==    by 0x61622B: delete_thread_infrun_breakpoints (infrun.c:2928)
==32510==    by 0x6162EF: for_each_just_stopped_thread (infrun.c:2958)
==32510==    by 0x616311: delete_just_stopped_threads_infrun_breakpoints (infrun.c:2969)
==32510==    by 0x616C96: fetch_inferior_event (infrun.c:3267)
==32510==    by 0x63A2DE: inferior_event_handler (inf-loop.c:57)
==32510==    by 0x4E0E56: remote_async_serial_handler (remote.c:11877)
==32510==    by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137)
==32510==    by 0x4AF6F0: fd_event (ser-base.c:182)
==32510==    by 0x63806D: handle_file_event (event-loop.c:762)
==32510==  Address 0xcf333e0 is 16 bytes inside a block of size 200 free'd
==32510==    at 0x4A07577: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==32510==    by 0x77CB74: xfree (common-utils.c:98)
==32510==    by 0x5AA954: delete_breakpoint (breakpoint.c:14056)
==32510==    by 0x5988BD: update_breakpoints_after_exec (breakpoint.c:3765)
==32510==    by 0x61360F: follow_exec (infrun.c:1091)
==32510==    by 0x6186FA: handle_inferior_event (infrun.c:4061)
==32510==    by 0x616C55: fetch_inferior_event (infrun.c:3261)
==32510==    by 0x63A2DE: inferior_event_handler (inf-loop.c:57)
==32510==    by 0x4E0E56: remote_async_serial_handler (remote.c:11877)
==32510==    by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137)
==32510==    by 0x4AF6F0: fd_event (ser-base.c:182)
==32510==    by 0x63806D: handle_file_event (event-loop.c:762)
==32510==
[Switching to Thread 32509.32532]

Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29
29        if (execl (image, image, NULL) == -1)
(gdb)

The breakpoint in question is the step-resume breakpoint of the
non-main thread, the one that was "next"ed.

The exact same issue can be seen on mainline with native debugging, by
running the thread-execl.exp test in non-stop mode, because the kernel
doesn't report a thread exit event for the execing thread.

Tested on x86_64 Fedora 20.

gdb/ChangeLog:
2015-03-02  Pedro Alves  <palves@redhat.com>

	* infrun.c (follow_exec): Delete all threads of the process except
	the event thread.  Extended comments.

gdb/testsuite/ChangeLog:
2015-03-02  Pedro Alves  <palves@redhat.com>

	* gdb.threads/thread-execl.exp (do_test): Handle non-stop.
	(top level): Call do_test with non-stop as well.
2015-03-03 01:25:17 +00:00

79 lines
2.2 KiB
Plaintext

# Copyright (C) 2009-2015 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Test that GDB doesn't get stuck when stepping over an exec call done
# by a thread other than the main thread.
# There's no support for exec events in the remote protocol.
if { [is_remote target] } {
return 0
}
standard_testfile
if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \
executable debug] != "" } {
return -1
}
# Run the test proper. SCHEDLOCK specifies what scheduler-locking
# should be set to.
proc do_test { schedlock } {
global binfile
if {$schedlock == "non-stop"} {
set prefix $schedlock
} else {
set prefix "schedlock $schedlock"
}
with_test_prefix "$prefix" {
clean_restart ${binfile}
if {$schedlock == "non-stop"} {
gdb_test_no_output "set non-stop 1"
}
if ![runto_main] {
return 0
}
# Get ourselves to the thread that execs.
gdb_breakpoint "thread_execler"
gdb_test "continue" ".*thread_execler.*" "continue to thread start"
if {$schedlock == "non-stop"} {
gdb_test "thread 2" \
"Switching to .*thread_execler.*" \
"switch to event thread"
}
# Now set a breakpoint at `main', and step over the execl call. The
# breakpoint at main should be reached. GDB should not try to revert
# back to the old thread from the old image and resume stepping it
# (since it is gone).
gdb_breakpoint "main"
if {$schedlock != "non-stop"} {
gdb_test_no_output "set scheduler-locking $schedlock"
}
gdb_test "next" ".*main.*" "get to main in new image"
}
}
foreach schedlock {"off" "step" "on" "non-stop"} {
do_test $schedlock
}